This example shows a smiley face built with React and D3, rendered as SVG. It demonstrates how to compose reusable React components for static shapes: a yellow background circle with a black stroke, two black eye circles, and a mouth drawn as an arc path. The D3 `arc` generator defines the mouth’s inner and outer radii, start and end angles, and stroke width, with positioning handled via SVG group transformations. The code uses React 17, D3 v5, and the `arc` API in a declarative, data-driven layout.